Traffic laws and regulations dictate that various lamps or lights be provided in an automobile for warning or notifying drivers in other cars or pedestrians of the condition of the automobile. For prevention of rear-end collisions it is preferable that the drivers of trailing cars be properly notified of the condition of a preceding car so as to apply a suitable braking operation. At the present time, there is provided only a stop light or lights for warning drivers of trailing cars of a braking action. Thus, there is not any means for warning or notifying the drivers of trailing cars of various operating conditions including accelerating operations and engine braking operations of a preceding car.